1. Field of the Invention
The present invention relates to a touch activated controller which includes a control pad and which permits sliding action control by movement of a finger or thumb upon a surface of the control pad without the need for the operator to lift his finger or thumb from the control pad surface throughout use of the device.
2. Description of the Prior Art
It is well known to use an operator input device to control a cursor or other controlled object on the screen of a cathode ray tube. For example, in the field of computer controls, many devices exist for use in cursor control, including sophisticated proportional movement control devices such as mouse devices, trackballs, light pads, and various types of sensory touch pads. Two known capacitive activated computer control devices are described in Matske et al, U.S. Pat. No. 4,736,191 and Bobick, U.S. Pat. No. 4,103,252. However, computer controls are not particularly adaptable for use in the control of video games since computer control needs differ so significantly from video game control needs. In computer operation, the operator is principally engaged with character entry via keystroke operation of a keyboard and only occasionally must remove his fingers from the character entry keys to operate the cursor movement control keys or some other cursor control device. Under the usual computer operating conditions, the operator tends to direct his attention to cursor movement control intermittently, as the need arises. Typically, the computer operator does not rest his finger on the cursor control device as this would bring about a spurious movement response and interfere with his operation of the keyboard keys. Thus, in computer operation, the typical mode of operation of the cursor controller is momentary and only intermittent.
The operation of some devices, as for example, the operation of video games calls for a different type of movement control. For example, in the operation of video games the operator will constantly have his thumb, finger or hand in contact with the motion control device. An important feature of such devices is that the operator be able to maintain such constant contact with the control device without inducing an unintentional response. For example, during use of the typical joystick used for movement control in video games, the operator will customarily grasp the joystick in some neutral position in preparation for rapid repositioning of the joystick out of the neutral position to bring about the next positive movement control.
Similarly, in the use of rocker motion paddle devices, where electrical switches are activated by mechanically depressing the rocker paddle from a neutral position to cause an electrical switch closure and bring about a movement response in a controlled object, the usual practice is to maintain very low pressure contact with the rocker pad switch surface so that when the next movement is required, the response time is minimized between the perceived need for motion and the activation of the motion-controlling switch pad. A positive feature of mechanical switching devices that require pressure for activation is that one can maintain his finger or hand in contact with the device surface without inducing an unintentional switch closure and response. This feature is very important in the control of video games and the like calling for very rapid motion control. However, problems exist in the use of rocker motion paddle devices. In the control of video games, the present level of development calls for operator input devices which provide four direction or eight direction control over movement of the controlled object on the video screen. Control devices such as four or eight position rocker paddle switch pads and various joystick, trackball, and other mechanically activated devices are well known but such mechanical motion controllers are tiresome to use and limit the speed at which an operator can execute control commands.
Computer control devices which are not of the mechanically activated type are known in the art. For example, U.S. Pat. No. 4,736,191 to Matske et al referred to above is a capacitive activated proportional movement control touch pad for computers. Matske et al show a number of capacitive reactive sensor plates arranged as sectors radiating from the center of a circle. However, the center as well as the surrounding sectors of the Matske et al device contain electrodes for detecting motion. Thus, Matske provides no neutral zone where an operator may rest his finger between various movements. This type of touch activated control device will not work well for video game control because it does not provide for the possibility of continuous contact with the pad surface without inducing unwanted motion response.
U.S. Pat. No. 4,103,252 to Bobick referred to above is another example of a computer control device which is not of the mechanically activated type. Bobick describes proportional control over a controlled object by sensing the relative position of an object and four interdigitated electrodes arranged in a circle along two orthogonal axes. Like Matzke et al, the Bobick device does not include a null zone where an operator may rest his finger without eliciting an unwanted control signal response.
In the use of capacitance activated control devices such as those described in the Matske et al and Bobick patents, a control response may also occur accidentally if the operator's finger unintentionally comes into close proximity to or touches the surface of an electrode. This can occur when the finger approaches the response pad surface from too low a path, as might occur with any of the known capacitive responsive inventions.
Another problem is that in video game play, the operators attention is focused almost entirely on the video display screen rather than on the surface of the game controller pad. Thus a sliding motion touch pad that is completely smooth will provide little information to the game player regarding the position of his finger on the control pad surface.
In considering the control circuitry required to operate devices of the type described herein, there are various means for measuring an electrical capacitance or more specifically a change in capacitance due to the presence of an external object such as a finger placed in the vicinity of a sensor electrode. One known means utilizes the capacitance of a sensor plate as part of an RC oscillator circuit. Placing an object near the sensor plate changes the capacitance of the circuit and hence the frequency of oscillation. Thus the presence or absence of an object near the sensor electrode will be indicated by a change in the frequency. This is the means used in U.S. Pat. No. 4,103,252 referred to above. One problem with this means is that there will be cross-coupling of the various oscillators.
Another known means of measuring capacitance is to apply an electrical voltage step to one end of a resistor which is connected on the other end to a capacitive sensor plate. The current through the resistor charges the capacitive sensor causing its voltage to change in accordance with well known principles of electrical RC circuits. The sensor voltage will change more rapidly with less capacitance and more slowly with larger capacitance, as is the case when an object is near the sensor plate. Thus the timing or more specifically the delay of the voltage change is an indication of an object near the sensor. To provide a useful output signal, the time delay of the signal must be compared to the fixed time delay of a reference circuit. This means is used in U.S. Pat. No. 4,595,913 to Aubuchon.
In view of the foregoing, it is an object of the present invention to provide a touch activated switch pad that will permit sliding action control by movement of an object such as a finger without the need for the operator to lift his finger from the pad between control movements or when moving from one sensory electrode to another.
It is a further object of the present invention to provide such a touch activated switch pad which will enable a user to elicit a control switching response in eight directions through the utilization of only four electrodes.
It is a further object of the invention to provide a sliding contact touch activated switch pad having a central null zone that will accommodate the operator's digit pad thereon without causing a movement response of the controlled object.
It is another object of the invention to provide a controller where the operator's digit pad may be slid from the null zone onto any one of the surrounding electrode pads without the need for lifting the operator's finger from the pad, to accomplish a single final control switching response when only one sensor pad is at least partly covered by an operator's digit pad, and no switching response when the operator's digit pad lies within a centrally located null zone.
Another objective of the invention is to provide a dual final control switching response when any two adjacent electrodes are at least partly covered by a controlling object such as the operator's digit pad.
A further objective of the invention is to provide a sliding contact control interface device where the operator's digit pad can slide about on the control pad surface continuously, eliciting no switching response when the digit pad rests substantially entirely within a defined central null zone, a single final control switching response when the operator's digit pad rests at least partly in contact with a single electrode pad, and a dual final control switching response when the operator's digit pad rests at least partly in contact with any pair of adjacent electrodes.
Another objective of the invention is to provide a sliding contact control interface device within a confined space so that the entire surface of the switch pad can be accessed merely by sliding the digit pad about on the control pad surface, without the need to raise or reposition the operator's wrist from a beginning position.
A further object of the present invention is to provide such a touch activated switch pad which includes a null zone at the center of the pad so that the operator can rest his finger between movement commands without the need to lift his finger from the pad surface.
It is a further object of the present invention to provide such a touch activated switch pad having a surface with patterned contours that are useful in providing the operator with tactile feedback useful in identifying the position of his finger on the pad without the need for visual confirmation.
Another object of the present invention is to provide a touch activated switch pad that is both simple and intuitive to operate.
Yet another object of the present invention is to provide an improved touch activated switch pad for use with a video game.
A further object of the present invention is to provide a touch activated switch pad that is less fatiguing to operate than mechanically operated switching devices.
It is a still further object of the present invention to provide a touch activated switch pad that enables the operator to accomplish faster video game play and speed of response.
Another object of the present invention is to provide a touch activated switch pad that facilitates carrying out complex movements such as circular control action that ordinarily is very difficult to achieve with conventional mechanical rocker pad or joystick controllers.
It is a further object of the present invention to provide a touch activated switch pad which includes control circuitry which does not utilize variable frequency oscillators or signal time delays.